Field of the Invention
The present invention relates to a disk, a wind instrument, a counter piece, and a method of producing the disk.
Discussion of the Background
Musical wind instruments such as brass instruments and woodwind instruments, particularly flutes, allow the musician to play different tones by opening and closing a plurality of tone holes with his fingers. Typically, the musician places his/her fingers on the plural keys of the instrument's key mechanism or key work which allows, upon direct or indirect (via a lever) actuation of the musician's fingers, for placing each of a plurality of key cups onto the plural tone holes.
The sound quality of the wind instrument largely depends on the exactness of the closure of its tone holes by the key cups. Ideally, the cup should close the tone hole in an airtight manner so that the instrument main body and the cup vibrate together like a single uniformly sounding body. If the key cup does not fit precisely on the tone hole, a portion of air could emanate from the closed hole during playing, thereby producing some undesirable whistling sound. In order to ensure an airtight fitting of the cup on the tone hole, the cup usually contains a pad assembly comprising a felt body coated with a resin film or some sort of animal skin.
In order to better support the pad assembly within the key cup it is also known to put a stabilising disk between the inner bottom wall of the cup and the pad assembly. The stabilising disk is typically made of a plastics material formed by injection moulding or the like. Such stabilising or backing disks improve the seating of the pad assembly within the cup and achieve a reasonably tight closure of the tone hole by the key cup even when the wind instrument is used for a long lifetime.
A problem arises from the fact that the inner bottom wall of the cup mostly has a non-flat surface. This means that the inner bottom wall has some unevenness in the sense that it is not rotationally symmetrical with respect to its centre point. This non-flatness or unevenness can be originally existent due to an imperfect machining or working process of the cup or arise during use of the instrument as a common wear behaviour. The uneven surface of the inner bottom wall leads to a tilting movement of the stabilising disk and the pad assembly within the cup. As a result, the cup fails to close the tone hole in an airtight manner.
It can be attempted to avoid this problem by increasing the pressure by which the pad assembly rests on the tone hole, but this causes further problems because of the higher pressing force to be applied by the musician for closing the cups via the key mechanism and because of the unbalanced load or pressure applied to the pad assembly along its circumference.
In order to balance out the uneven surface structure of the inner bottom wall in the cup, specialists for repairing musical wind instruments have developed a method of attaching thin shimming elements of cardboard material or the like to those circumferential portions of the pad assembly which are opposite to the deeper portions of the uneven surface of the bottom wall within the cup. Thereby, the unevenness can be balanced out and the instrument's sound quality can be restored. However, this repairing process is very cumbersome and time-consuming and requires a high level of skills and expertise. It would thus be desirable to find an easier and more efficient way of balancing out the non-flat surface of the inner bottom wall in the cup.
It has previously been known to fill the inner bottom wall with bees wax or sealing wax (such as shellac) before inserting the pad assembly. U.S. Pat. No. 3,421,399 and FR1304749 relate to this conventional technology. However, those waxes are malleable (i.e. in a molten or softened state, or plastically ductile) at relatively low temperatures around room temperature so that backing disks made therefrom give no durable stabilisation of the pad assembly during use of the wind instrument and lead to undesired sound characteristics of the instrument. Also, due to its insufficiently stable backing by the layer of bees wax or sealing wax, the pad assembly often gets tilted and non-uniformly worn during actual use in the key cup.
A problem arises when repairing a musical instrument; namely the conventional stabilising disk attached onto the inner bottom wall of the cup by means of a sealing wax or a glue, or a stabilising disk tightly stuck by itself onto the inner bottom wall of the cup due to deterioration of the stabilising disk material during the use of the musical instrument, needs to be completely removed from the surface of the inner bottom wall of the cup. However, removal of such stabilising disk is often not easy even for the repair specialist because it is too tightly adhered or stuck onto the inner bottom wall of the cup.
U.S. Pat. No. 5,717,151 discloses a stabilising disk consisting of two components, an upper component formed of an adjusting agent, particularly a hot melt adhesive, and a second component formed of a metal or polymer material. The first and second components are glued together. The adjusting agent is poured in its fluid state into the cup and the second component is then pressed thereon to establish a gluing connection between the two components. There are grooves or porous regions formed in the second component into which the adjusting agent is pressed during the gluing step. The pressing force is exerted by an adjusting disk which is driven by magnetic or vacuum forces.
A disadvantage of the above described stabilising disk known from U.S. Pat. No. 5,717,151 resides in its complicated setup of two components and the fact that the adjusting agent has a sticky consistence at room temperature which makes it difficult to remove the stabilising disk entirely from the cup in maintenance works. Further, the pressing of the two components by vacuum or magnetic forces via the adjusting disk is rather complicated and impedes manual fine tuning. It would therefore be desirable to have a less complicated manufacturing method by which a stabilising disk is formed as an integral body. The stabilising disk should have a shape which is complementary to the uneven inner surface of the cup and which is nevertheless readily removable from the cup in the manufacturing, repairing or maintenance process of the wind instrument.
Another problem generally impairing the tone hole closure by the key cup resides in the fact that the key mechanism or key work does not work so precisely that the key cup comes at rest on the tone hole in a perfectly horizontal orientation, i.e. an orientation in which the pad assembly in the cup is completely parallel to the outer circumference of the tone hole. More likely, the pad assembly reaches the tone hole's outer circumferential portion at a slightly inclined angle which means a rotationally asymmetric closure of the tone hole and a non-uniform pressing force against the pad assembly during use. This inclined angle might result from long-term use of the instrument or be originally existent due to an imperfect constructional manufacturing process.
As a result of the above-explained inclined angle, even a stabilising disk which would perfectly balance out any unevenness (non-flatness) in the surface structure of the inner bottom wall of the cup would lead to a non-perfect horizontal closure of the tone hole by the pad assembly. The pad assembly would then perfectly rest in the cup in a horizontal fashion but be positioned obliquely onto the tone hole during use of the wind instrument due to the imprecise mechanism by which the key cup is hinged to the key work.
Also, as a result of the above-mentioned problems, the quality of the tone generated from the instrument by a player sometimes becomes inferior or too metallic, or the volume of the sound becomes lowered.